Tom Bosley, 83, a Tony Award-winning stage actor who enjoyed a long career on television, notably as the mild-mannered Cunningham patriarch on "Happy Days," a mild-mannered sheriff on "Murder, She Wrote" and a mild-mannered priest-detective on "Father Dowling Mysteries," died Oct. 19 at a hospital in Rancho Mirage, Calif. He had lung cancer.

Portly and soft-featured, Mr. Bosley cultivated an avuncular public persona in his best-known roles. But if there seemed an additional poignancy to Mr. Bosley's death, it was probably because he died three days after Barbara Billingsley, who played the wholesome mother of the Cleaver clan on "Leave It to Beaver."

Just as Billingsley helped define the cultural ideal of American suburban motherhood in the 1950s, Mr. Bosley did the same for middle-American fatherhood in "Happy Days," which was set in Milwaukee in the 1950s and aired from 1974 to 1984 on ABC.

Mr. Bosley was not the original Howard Cunningham, a married hardware store owner with two kids, Richie (played by Ron Howard) and Joanie (Erin Moran). Actor Harold Gould played Howard Cunningham in a 1972 episode of "Love, American Style," an ABC comedy anthology show.

But Gould was unavailable when the network decided to move forward with a separate "Happy Days" series building off the appeal of nostalgia spurred in part by movie successes such as George Lucas's "American Graffiti" (1973).

Mr. Bosley was a core part of the ensemble cast, which included Henry Winkler as the hip-talking motorcycle lothario Arthur "Fonzie" Fonzarelli. The Fonz and his gestures of coolness - thumbs-up, the happy cry of "Aaayy!" - offered a comic contrast to the square lifestyle personified by the Cunningham family. To the Fonz, Howard Cunningham was strictly "Mr. C."

If not terribly innovative by critical standards, "Happy Days" was nonetheless influential as a commercial juggernaut. Its self-titled theme song became a pop hit, and the show led to spinoff sitcoms including "Laverne & Shirley" and "Mork & Mindy."

"I think our timing was very right," Mr. Bosley told the Associated Press in 1984. "We were just coming out of the hippie era, where the moral fiber of the family was in jeopardy. I don't say it's been entirely restored, but I think we've been a major influence in getting people to look at themselves."

The show made Mr. Bosley a household name and helped sustain a front-ranked career for many years to come.

He had initially burst to acclaim in 1959 in the title role of the musical "Fiorello!," which traced the rise of the charismatic politician Fiorello LaGuardia from young lawyer and congressman to reformist mayor of New York.

The play, which ran more than two years on Broadway, won a Pulitzer Prize for drama and featured a script by Jerome Weidman and George Abbott and music and lyrics by Jerry Bock and Sheldon Harnick, respectively.

Mr. Bosley, who was required to sing in several languages, won the 1960 Tony Award for best featured actor in a musical. New York Times theater critic Brooks Atkinson wrote that Mr. Bosley captured the "abundant energy and explosive personality" of the role.